What is the Greatest Common Factor of 1280 and 1285?

Greatest common factor (GCF) of 1280 and 1285 is 5.

GCF(1280,1285) = 5

We will now calculate the prime factors of 1280 and 1285, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 1280 and 1285.

How to find the GCF of 1280 and 1285?

We will first find the prime factorization of 1280 and 1285. After we will calculate the factors of 1280 and 1285 and find the biggest common factor number .

Step-1: Prime Factorization of 1280

Prime factors of 1280 are 2, 5. Prime factorization of 1280 in exponential form is:

1280 = 2⁸ × 5¹

Step-2: Prime Factorization of 1285

Prime factors of 1285 are 5, 257. Prime factorization of 1285 in exponential form is:

1285 = 5¹ × 257¹

Step-3: Factors of 1280

List of positive integer factors of 1280 that divides 1280 without a remainder.

1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 256, 320, 640

Step-4: Factors of 1285

List of positive integer factors of 1285 that divides 1280 without a remainder.

1, 5, 257

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 1280 and 1285. The biggest common factor number is the GCF number.
So the greatest common factor 1280 and 1285 is 5.

Also check out the Least Common Multiple of 1280 and 1285